Multi Tier Models: In software engineering, multi-tier architecture (often referred to as n-tier architecture) is a client–server architecture in which presentation, application processing, and data management functions are physically separated

Types of Multi Tier Models:1. Traditional Mainframe model2. Client/ Server Model3. 3-tier Model 4. n-tier model

Some key terms to understand modelspresentation : A presentation is the process of presenting a topic to an audience

Processing: a process is an instance of a computer program that is being executed. It contains the program code and its current activity

Bussiness Rule: business logic or domain logic is the part of the program that encodes the real-world business rules that determine how data can be created, displayed, stored, and changed.

Data Storage and Data Transection:- To storig the data and how it is used in applications

Work Station:A workstation is a special computer designed for technical or scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi-user operating systems

1. Traditional Mainframe model-

Pros: Cons:1:Centralized – Changes inthe central system reflectson all clients.2: Less systems to maintain

1: High requirements for CPUon central system.2: Dumb terminals.

.2. Client/Server Model: The client–server model of computing is a distributed

application structure that partitions tasks or workloads between the providers of a resource or service, called servers, and service requesters, called clients. Often clients and servers communicate over a computer network on separate hardware, but both client and server may reside in the same system. A server host runs one or more server programs which share their resources with clients

Pros Cons1:Processes are distributedbetween server and the client.2:Performance is improvedbecause of the less utilizationof resources.

1:Networking speed andreliability are the majorbottleneck.2:Three systems to maintain.

3. 3-tier Model: Three-tier architecture is a client–server architecture in which the user interface, functional process logic("business rules"), computer data storage and data access are developed and maintained as independent modules, most often on separate platforms.

Pros Cons Network traffic is reduced,less data is passed to theclient and traffic to theRDBMS is filtered throughApp server. Performance is furtherimproved since therequirements are distributedbetween more systems

Four (including file server)systems to maintain.

N-tier Architecture-3 or more tiers architecture

PeopleSoft Internet Architecture

Web BrowserThe web browser is the primary means by which end users and even administrators accessPeopleSoft applications and administrative tools.

Web ServerA Java-enabled web server is required to support browser transaction requests and theapplication messaging technology. You install on the web server a collection of PeopleSoftJava servlets designed to handle a wide range of PeopleSoft transactions.

Application ServerThe application server is the core of the PeopleSoft Internet Architecture; it executes businesslogic and issues SQL to the database server. The application server consists of numerousPeopleSoft services and server processes that handle transaction requests.The application server is responsible for maintaining the SQL connection to the database forthe browser requests and the Windows Development Environment.PeopleSoft uses TUXEDO to manage database transactions, and Jolt, TUXEDO's counterpart,to facilitate transaction requests issued from the Internet. Both TUXEDO and Jolt areproducts of BEA Systems.

Database ServerThe database server houses your database engine and your PeopleSoft database, whichincludes all of your object definitions, system tables, application tables, and data. Thedatabase server must be running one of the supported RDBMS/operating systemcombinations.

The relationship between a database server and an application server is a one-to-many model.That is, a single database server can have multiple application servers connecting to it. Thedatabase server simultaneously handles the application server connections, DevelopmentEnvironment connections, and batch programs running against it.

Batch ServerThe batch server, or batch environment, is where you have PeopleSoft Process Schedulerinstalled and configured, and it is the location where many of your batch programs run, suchas Application Engine programs. In most situations this is also where you have your COBOLand SQR executables installed

web server:

The following list presents the software that runs on the PIA web server:

Web services The program installed on the host system that manages the web server, such as WebLogic or WebSphere.

Servlet Engine The environment in which servlets run. This component is tied to the web services software, but in some cases you install it separately.

Java Servlets A platform-independent programming language used widely for web-based programs. Servlets are Java programs that run on the web server. The Java executables are required for the servlet engine to operate.

PeopleSoft Servlets The following list contains the PeopleSoft servlets that reside on the web server.

Portal Servlet The Portal servlet handles all of the requests and formatting for the users accessing PeopleSoft through the PeopleSoft Portal. It also manages all aspects of the PeopleSoft Portal such as search, content management, and home page personalization.

Integration Gateway Servlet The Messaging Gateway servlet transmitspublish/subscribe messages between message nodes. Thegateway handles PeopleSoft-to-PeopleSoft messages,PeopleSoft-to-third party messages, and third party-to-PeopleSoft messages.

Report Repository Servlet The Report Manager servlet enables users to easily accessand distribute the output of batch reports, such as Crystaland SQR, run through PeopleSoft Process Scheduler overthe Internet. This servlet retrieves the report output in theReport Repository and serves it to the browser.

JoltThe PeopleSoft servlets on the web server transmit requests and data through a connection toJolt, which runs on the application server. Jolt extends Tuxedo's capabilities to the Internet; itis the communication layer between the web-based environment and the C++ environments.You configure the servlets to direct requests from the web server to a pre-defined Jolt port onthe application server.Jolt is a companion product that must coexist with Tuxedo on the same application servermachine. Jolt is not a standalone product; it can’t function without Tuxedo.

Tuxedo BEA Tuxedo provides platform independent communicationlayer between the client and the PeopleSoft serverprocesses. Tuxedo manages the connects to the app server, spawnsand decays the internal processes depending on theworkload.

The Application Server

The application server is the core of PeopleSoft Pure Internet Architecture; it carries out business logic and issues SQL to the database server. The application processing logic that ran on the client in previous releases now runs on the application server. The application server consists of numerous PeopleSoft services and server processes that handle transaction requests. These include requests to:

• Authenticate users.

• Build application pages.

• Save application pages.

• Run some PeopleCode.

• Run SQL (prompts, page-specific SQL, validations, and so forth).

The application server is responsible for maintaining the SQL connection to the database for the browser requests and the Windows development environment. PeopleSoft uses Tuxedo to manage database transactions and Jolt, Tuxedo's counterpart, to facilitate transaction requests issued from the internet. Both Tuxedo and Jolt are products of Oracle Systems.

The Portal Processor runs as an application service of the PeopleSoft application server. It runs with the other application services, such as the Component Processor, Security Manager, and SQL Access Manager. Portal Processor tasks include:

• Fetching content templates from the database.

• Fetching content references from the database portal registry and caching them in the application server portal registry.

• Processing personalizations.

• Interacting with other application services (lightweight directory access protocol (LDAP), role-based security, and so forth).

Application Servers Contains......

• Domains.

• Listeners, handlers, and queues.

• PeopleSoft server processes.

• Services.

• Oracle products.

• Database connectivity

DomainsAn application server domain is the collection of Server Processes, supporting processes, andresource managers that enable connections to the database.There can be a one-to-one or a many-to-one relationship between application server domainsand a database.

Listeners, handlers, and queues

Listeners, handlers, and queues provide the basis of the application server functionality. Understanding the role of each element is essential when you configure and tune your application server. For instance, although you need to know how to configure multiple Java server handlers, you also need to know why and when to perform this task.

The following diagram illustrates application server processes:

Item Description

Workstation listener (WSL)

The workstation listener monitors Oracle Tuxedo ports for initial connection requests sent from the PeopleTools development environment. After the workstation listener accepts a connection from a workstation, it directs the request to a workstation handler. From that point, the Microsoft Windows workstation interacts with the workstation handler to which it is assigned.

Workstation handler (WSH)

The workstation handler processes the requests that it receives from the workstation listener. A unique port number identifies a workstation handler. The port numbers for the workstation handler are selected (internally by Oracle Tuxedo) from a specified range of numbers. You can configure multiple workstation handlers to take care of demand increases; new processes are created as other processes become overloaded.

Oracle Jolt server listener (JSL)

The Oracle Jolt server listener applies only to browser requests. The Oracle Jolt server listener monitors the Oracle Jolt port for connection requests sent from the browser through the web server. After the Oracle Jolt server listener accepts a connection, it directs the request to an Oracle Jolt server handler. From that point, the browser interacts with the Oracle Jolt server handler. This is analogous to the relationship between the workstation server listener and workstation server handler.

Oracle Jolt server handler (JSH)

The Oracle Jolt server handler applies only to browser requests. The Oracle Jolt server handler processes the requests that it receives from the Oracle Java server listener. The port numbers for the Oracle Jolt server handler are selected internally by Oracle Tuxedo in sequential order.

Request queues

Each type of server process has a service request queue that it shares with other servers of the same type (as in PSAPPSRV on APPQ and PSQCKSRV on QCKQ). The workstation handler and Oracle Jolt server handler insert requests into the appropriate queue, and then the individual server processes complete each request in the order that it appears.

Server processes

The server processes act as the heart of the application server domain. They maintain the SQL connection and make sure that each transaction request gets processed on the database and that the results are returned to the appropriate origin.

PeopleSoft Server Processes

Multiple server processes run in an application server domain. A server process is executable code that receives incoming transaction requests. The server process carries out a request by making calls to a service, such as MgrGetObject.

Server processes invoke services to perform application logic and issue SQL to the RDBMS. Each application server process, such as PSAPPSRV, PSQCKSRV, PSQRYSRV, PSSAMSRV, or PSOPTENG, establishes and maintains its own connection to the database.

The server process waits for the service to finish, then returns information to the device that initiated the request, such as a browser. While a server process waits for a service to finish, other transaction requests wait in a queue until the current service finishes. A service may take a fraction of a second to finish or several seconds, depending on the type and complexity of the service. When the service finishes, the server process is then available to process the next request in the corresponding queue.

You need to configure only those server processes that your implementation requires per domain. The minimum server processes that a domain requires are PSAPPSRV and PSSAMSRV.

The following list describes the possible server processes included in an application server domain. Depending on the configuration options that you choose, not all of the server processes will necessarily be a part of every domain.

Process Discription

• PSAPPSRV • Generates HTML page based on the request.

• provides the memory and disk-caching feature for PeopleTools objects on the application server.

• PSAPPSRV is required to be running in any domain.

• PSQCKSRV • This process performs quick, read-only SQL requests.

• This is an optional process designed to improve performance by reducing the workload of PSAPPSRV.

• PSQRYSRV • This process is designed to handle any query run by PeopleSoft Query.

• This is an optional process designed to

improve performance by reducing the workload of PSAPPSRV.

• PSSAMSRV Handles the requests that is mainly

associated with PeopleSoft Application Designer. Thisprocess is required to be running on any domain.

• PSOPTENG This optimization engine process provides optimization services in PeopleSoft Optimization Framework. You need to configure this process in a server domain only if you want to use the optimization plug-in delivered with PeopleSoft applications.

The following set of server processes is used for application messaging. (Your messaging domain must also contain PSAPPSRV and PSSAMSRV, the required server processes.)

• PSMSGDSP

• PSMSGHND

• PSPUBDSP

• PSPUBHND

• PSSUBDSP

• PSSUBHND

Services

When a PeopleSoft application sends a request to the application server, it sends a service name and a set of parameters, such as MgrGetObject and its parameters. Oracle Tuxedo then queues the transaction request to a specific server process that is designed to handle certain services.

When a server process starts, it advertises to the system the predefined services it handles. You can see the association between the many services and server processes by reviewing the PSAPPSRV.UBB file.

Oracle Middleware

PeopleSoft software uses Oracle Tuxedo, a middleware framework and transaction monitor, to

manage database transactions. PeopleSoft software also uses Oracle Jolt, a Java API and class library, as the layer that facilitates communication between the PeopleSoft servlets on the web server and the application server. Both Oracle Tuxedo and Jolt are required.

Although we document the Oracle components with respect to their function within the context of a PeopleSoft environment, we do not duplicate the documentation provided by Oracle. You should become familiar with the Oracle documentation that we ship along with our products. The Oracle documentation provides an extensive error catalog that serves as an invaluable source of information when you are troubleshooting.

Note: Oracle Tuxedo doesn’t actually perform processing on the application server; it schedules PeopleSoft server processes to perform the transactions.

Database Connectivity

Application servers require database connectivity software to be installed locally to maintain the SQL connection with the RDBMS. You must install the required connectivity software and associated utilities for your RDBMS.

After the application server establishes a connection to the database, any device that initiates a transaction request through the application server takes advantage of the application server's direct connection to the database and therefore requires no connectivity software.

PeopleSoft DatabasePeopleSoft has a long history of offering customers a choice of market-leading databases. PeopleTools provides an abstraction layer, which insulates application developers from the intricacies of each of the specific database platforms. Customer databases choices include:

•Oracle

•IBM DB2

•Microsoft SQL Server

•Informix

•Sybase

After you install your database engine there are three distinct layers within the database that work in concert to store and manage data for your PeopleSoft system. The database system tables manage both the PeopleTools and PeopleSoft application database objects, while the PeopleSoft application tables reside within the infrastructure defined by the PeopleTools metadata.

PeopleSoft database comprised of distinct, yet integrated, layers including system tables, PeopleTools metadata, and PeopleSoft application dataThe following table describes each layer of a PeopleSoft database.

PeopleSoft Database Layer Description

System Tables

System tables, also called system catalog tables, are analogous to a table of contents for a book or to file allocation tables on a hard drive. The structure and table names vary depending on which RDBMS you use. System catalog tables:• Keep track of all of the objects that reside in the database

instance.

• Are created by and owned by the RDBMS.

• Are often described as system metadata.

PeopleTools metadata

PeopleTools tables provide the infrastructure for PeopleSoft applications by storing and managing PeopleSoft application metadata. This metadata consists of information that defines the application, such as records, fields, pages, PeopleCode, and security. PeopleTools tables:• Define the structure of all object definitions that make up an

application.

• Use the same table structure for all applications.

• Contain data that is added and updated only when the application is installed, or when using development tools such as PeopleSoft Application Designer or Data Mover.

PeopleSoft application data tables

Application data tables store data entered through a PeopleSoft application. The specific tables and their structures vary by application. Application data tables:• Contain transactional data entered by users.

• Are empty prior to data entry (except the demo databases).

PeopleSoft Batch Server Batch environment allows you to run preprogrammedroutines, either on demand or on a schedule. Common use of batch environment is to generate a reportand post it on a regular basis. In addition to reports, it is also used to schedule actual datachanges, such as posting entries to GL. Batch server also involves Tuxedo to manage theprocesses running on them.

Tracing The Connections

1. The link is interpreted as a URL by the browser, which includes the name of a servlet.2. The servlet started in the servlet engine interprets the request and comes up with a list of objects that are required to build the page.3. A request for all required objects is sent to the application server as a Jolt message.4. Tuxedo receives the Jolt message and converts it into a service request, which it routes to appropriate PeopleSoft server process.5. The PeopleSoft process converts service request into SQL statement.6.SQL statements are sent to the Database.7.The requested data is supplied by the database.

8. The PeopleSoft process constructs a HTML page out of object data.9. Tuxedo retrieves the HTML and Data from the PeopleSoft process.10. Data is forwarded by Tuxedo to the requesting Java servlet.11. The servlet forwards the requested page to the HTTP services after adding images, style sheets and java script.12. The HTTP service assembles and forwards the HTML page to the browser.13. The browser views the page.